Revisiting the constraints on primordial black hole abundance with the isotropic gamma-ray background
Abstract
We revisit the constraints on primordial black holes (PBHs) in the mass range 1013 g - 1018 g by comparing the 100 keV-5 GeV gamma-ray background with isotropic flux from PBH Hawking radiation (HR). We investigate three effects that may update the constraints on the PBH abundance; (i) reliably calculating the secondary spectra of HR for energy below 5 GeV, (ii) the contributions to the measured isotropic flux from the Galactic PBH HR and that from annihilation radiation due to evaporated positrons, (iii) inclusion of astrophysical background from gamma-ray sources. The conservative constraint is significantly improved by more than an order of magnitude at 2 ×1016 g ≲M ≲1017 g over the past relevant work, where the effect (ii) is dominant. After further accounting for the astrophysical background, more than a tenfold improvement extends to a much wider mass range 1015 g ≲M ≲2 ×1017 g .
- Publication:
-
Physical Review D
- Pub Date:
- March 2022
- DOI:
- 10.1103/PhysRevD.105.063008
- arXiv:
- arXiv:2112.15463
- Bibcode:
- 2022PhRvD.105f3008C
- Keywords:
-
- Astrophysics - Cosmology and Nongalactic Astrophysics;
- Astrophysics - High Energy Astrophysical Phenomena;
- High Energy Physics - Phenomenology
- E-Print:
- 9 pages, 6 figures, accepted for publication in Physical Review D